Speed UTV - discussion

[evantwheeler]

It literally makes my old X3 look like a long travel rhino.

The suspension is unreal, you can turn this car hard, and it just digs in.. REALLY REALLY IMPRESSED with the performance of the whole

Great to hear

 

[LargeOrangeFont]

FWIW the Maverick R looks to have a similar problem. You need a huge scoop with the windshield.

 

[DaveH]

We did take it off late last night. Ran 30-40 pretty hard miles.

View attachment 1280937
View attachment 1280937

Most the time
The car is in the 190’ish range on temp.. when we were rubbing the shit out of it we got it to 199.

Previously with the window on it was running upper 190’s then would start to spike and get to 215’ish before we’d stop and let it idle to cool off.

I have to go back and check the exact temps
When it started overheating but I believe it was 215-225 at peak..

did you put the windshield back on and run the same test in the cooler evening weather? still highly recommend check for air in the system.

 

[Bigbore500r]

After we spaced it last night I don’t believe that will be enough air.. it requires A LOT..

This isn’t just getting rid of dust it’s gotta have positive airflow for the radiator

Is the bottom of the car sealed, ,below the radiator?

My sandrail is a full-body car, with a solid floor, glass windshield, hard roof etc. Radiator is behind rear seats, not even up where it would get any airflow over the top. but....the solid floorpan stops and air can come in from below, maybe that's part of the difference? I also don't have window nets of course

 

[SeanRitchie]

Some were talking about the fan shroud around the radiator not being "sealed" around the radiator, which would allow the fans to pull air through the gap in the shroud, instead of through the radiator. Have you looked into that?

 

[LargeOrangeFont]

Some were talking about the fan shroud around the radiator not being "sealed" around the radiator, which would allow the fans to pull air through the gap in the shroud, instead of through the radiator. Have you looked into that?

Good call here.

 

[DaveH]

obvious question but the fans were running? what temp do they come on at? staged or do they come on all at once?

 

[Melloyellovector]

What fans are those? size and manufacture?
sandrails etc are nearly all rear radiator. windshields with full bodies is common on on every newer car built.
2 fans can keep a twin turbo car cool with zero problems.
likely needs radiator tilted back and better fan or shrouds
air flow in an enclosed body is less of an issue at all with correct placement of radiator and fan control

 

[SeanRitchie]

I am by no means an expert in air flow, but understand some basic principles.

I would think that having positive pressure directed at the radiator is not as important as you might think (no need for roof scoops). As long as there is access to "pull" air from in front of the radiator, whether that be from the sides, top, or bottom of the vehicle, then exhaust the hot air through the back of the radiator with the least amount of restriction, the fans should be able to accomplish the task of keeping the air moving.

Any circulation of air around the back of the fans, could restrict how much air the fans can "push" into that circulation. Think of the Mythbusters episode of figuring out best fuel economy on pickup trucks. They found that running with the tailgate up actually improves aerodynamics as the negative air behind the cab circulating around the bed created a "bubble" where the air coming over the cab would be pushed over the tailgate, instead of getting sucked against the back of the cab pulling the truck backwards in effect.

 

[rivermobster]

I hate to be Captain Obvious, but...

Every new engine runs HOT. There is a Lot of internal resistance until it is broken in Properly...

Multiple heat cycles, varying load (accel/decel) without excessively loading the engine. Normal brake in procedures?

If it was me...

Id probably get two to five hundred miles on it before I started fixing things.

 

[DaveH]

i would also confirm with a laser thermometer what the temp of the radiator is. the temp on your dash is likely from the EFI engine coolant sensor, much closer to the engine and there may or may not be a thermostat. if the radiator is significantly cooler then what the temp sensor reads, thats a sure sign of air in the system.

 

[Bigbore500r]

I hate to be Captain Obvious, but...

Every new engine runs HOT. There is a Lot of internal resistance until it is broken in Properly...

Multiple heat cycles, varying load (accel/decel) without excessively loading the engine. Normal brake in procedures?

If it was me...

Id probably get two to five hundred miles on it before I started fixing things.

That may be on the next episode of myth busters......

 

[Rayson1971]

With all this r&d you guys are doing, RG should listen and compensate. Lol

 

[monkeyswrench]

Echoing a couple thoughts here. As Mobster said, a fresh motor is tighter, and tends to run warmer. That mixed with assembly lube, and core junk from the castings may increase running temps. Also, as Sean said, getting air to the radiator is only half the job. The air has to pass through and beyond to extract heat.

Poor man's wind tunnel...big shop fan and a friend that vapes. It will let you see if your scoop is in the air flow, or in a low pressure area. You can also see it the air is passing the radiator unrestricted, or balling up with turbulence down stream, or stacking against a high pressure area created by accessories or something.

 

[RCDave]

Not really.. because most don’t run windshields.

Weirdly on this car most at the sand show did have windshields. (Which is backwards from normal)

He did put out a video before saying this was a problem and it is for cold weather and speeds below 50mph only.

He has bigger fish to fry right now and will likely circle back to this at a later date. For the time being the solution is fake it off.

Ahhh. Got it

 

[rivermobster]

I like @DaveH idea best...

Start with the Lazer temp gun to verify what really IS going on first.

Otherwise, you're maybe fixing a problem that doesn't exist?

 

[JLG614]

This is a great thread if it can stay like this and not start all the shit talking. I have done my fair share of shit talking but now that the cars are out I really want to see the real world performance of it good or bad. Dave is off to a great start actually talking about the good and bad things of the car so far.

The over heating is a little concerning seeing as its only 86 degrees. My twin turbo sand car is heavy with full body and windshield and doesn't go over 190 in the dunes no matter what I'm doing. Dave has made some good adjustments so far to try and correct the problem. A few things to try. Is there any panels in the front of the car that are removable? And i'm saying like even down by your feet in the front? I know how any full body cars can vortex so anything letting more forward air come through will help. Next thing I would do is very aggressive but probably the best option. Raise the radiator up 6-8" to give it as much direct air as possible. We have done this on every sand car in our fleet because builders always seem to put them in very low. Raising them up helps tremendously. This is about the dumbest thing I will say but always have to ask, The fans are blowing the right direction correct? dumbest thing ever but we have had cars in our group that were blowing the wrong way and over heating.

Please keep the updates coming!

 

[monkeyswrench]

I like @DaveH idea best...

Start with the Lazer temp gun to verify what really IS going on first.

Otherwise, you're maybe fixing a problem that doesn't exist?

Hadn't thought about gauge/sender inaccuracies. I know Chevy in the early 2000's had a fix for customer complaints of running hot...install a resistor on the gauge

 

[Outdrive1]

@RiverDave

Take the windshield off and test the car to make sure that is the problem

I said that since the first day, Dave refuses to try it without it on for some reason.

That scoop is bigger but still necks down to the old size, I can’t see how that would work without making the entire scoop capable of handling the air the inlet can grab. You want more volume, imo

 

[throttle]

I said that since the first day, Dave refuses to try it without it on for some reason.

That scoop is bigger but still necks down to the old size, I can’t see how that would work without making the entire scoop capable of handling the air the inlet can grab. You want more volume, imo

My thought too, compressing air / forcing more air into tight space it going to increase heat (I think).

 

[Gramps]

this might be a dumb idea but....what about a partial windshield? I have the "half" windshield on my RZR. It allows airflow high above the seats but it blocks wind in your face.

 

[throttle]

Noted "recovery kit" including a pair of shoes. My recovery kit includes a speed strap, just sayin.

Hey RD, did you find a way to tow it (previous video clip you mentioned "no tow hooks". Maybe on the roof for the helicopter to lift out (just teasin you), but really, its got to have a grab someplace to tow from, maybe not?.

kool whip for sure! Lots to get familiar with, have fun. Looking forward to seeing it up close soon.

 

[DaveH]

i have no doubt there is an airflow issue. i also have no doubt the reading on the dash is the correct reading that the ECU is seeing.

this will be made worse if there is air in the cooling system, hence the reason its so important to ensure there is no air in the system.

but back to airflow, to give you an idea of how windshields effect flow on rear radiators, i had a car in my shop a while back. Nice sand car, typical rear engine and radiator setup. during the wiring, i tested the SPAL fans. these were medium size fans, pulled about 16-17 amps each. So i wired these to a 20amp output from the PDM.

everything worked fine on the dyno.

first trip out customer complained car was over heating. brings it back, turns out the fans were drawing MORE power at speeds above 40mph then the 20amp circuit will allows, shutting the circuit down and the fans off.

how could this be? stands to reason that as the car picked up speed airflow would naturally move through the fan and electrical load on the motor would go DOWN. but exactly the opposite was happening.

well the only way to know for certain was either a wind tunnel or some aero sensors behind the fans to know what was really going on. I didnt go that far, but surmise it to say negative pressure behind the fan due to the windshield was causing the fans to work harder and pull more power then when the car was static. there was no fix other then to wire the fans to a higher amperage circuit, and this cured the problem. but the point is, aero can do funny things and going faster thinking you will move more air isnt necessarily the answer.

i would put some yarn on the fan shroud, put a gopro watching the fans and go test.

 

[2Driver]

It’s a race car get a couple Parker pumpers, breath easy and take the windshield off.

 

[yz450mm]

I said that since the first day, Dave refuses to try it without it on for some reason.

That scoop is bigger but still necks down to the old size, I can’t see how that would work without making the entire scoop capable of handling the air the inlet can grab. You want more volume, imo

Post 61 and 64.

 

[LargeOrangeFont]

i have no doubt there is an airflow issue. i also have no doubt the reading on the dash is the correct reading that the ECU is seeing.

this will be made worse if there is air in the cooling system, hence the reason its so important to ensure there is no air in the system.

but back to airflow, to give you an idea of how windshields effect flow on rear radiators, i had a car in my shop a while back. Nice sand car, typical rear engine and radiator setup. during the wiring, i tested the SPAL fans. these were medium size fans, pulled about 16-17 amps each. So i wired these to a 20amp output from the PDM.

everything worked fine on the dyno.

first trip out customer complained car was over heating. brings it back, turns out the fans were drawing MORE power at speeds above 40mph then the 20amp circuit will allows, shutting the circuit down and the fans off.

how could this be? stands to reason that as the car picked up speed airflow would naturally move through the fan and electrical load on the motor would go DOWN. but exactly the opposite was happening.

well the only way to know for certain was either a wind tunnel or some aero sensors behind the fans to know what was really going on. I didnt go that far, but surmise it to say negative pressure behind the fan due to the windshield was causing the fans to work harder and pull more power then when the car was static. there was no fix other then to wire the fans to a higher amperage circuit, and this cured the problem. but the point is, aero can do funny things and going faster thinking you will move more air isnt necessarily the answer.

i would put some yarn on the fan shroud, put a gopro watching the fans and go test.

This. Fans under power will stall at a certain airspeed and become a restriction. My race car ran hotter with the fans on all the time than with them set to shut off at 35 mph.

 

[LargeOrangeFont]

Noted "recovery kit" including a pair of shoes. My recovery kit includes a speed strap, just sayin.

Hey RD, did you find a way to tow it (previous video clip you mentioned "no tow hooks". Maybe on the roof for the helicopter to lift out (just teasin you), but really, its got to have a grab someplace to tow from, maybe not?.

kool whip for sure! Lots to get familiar with, have fun. Looking forward to seeing it up close soon.

Rear is easy, it has a standard tow hitch. Up front there is nothing if you don’t have a bumper.. but I wouldn’t trust anyway.

 

[HCP3]

Rear is easy, it has a standard tow hitch. Up front there is nothing if you don’t have a bumper.. but I wouldn’t trust anyway.

Easy if you don't have the optional rear skid plate. Otherwise you aren't securing a hitch/hook in the receiver until you cut the plate.

 

[DaveH]

This. Fans under power will stall at a certain airspeed and become a restriction. My race car ran hotter with the fans on all the time than with them set to shut off at 35 mph.

yes, and exactly why scoops may or may not do anything (or even make it worse). the problem may be at the fan shroud itslef and need additional ducting there or diverters to improve airflow in the back.

 

[SoCalDave]

Looking at the fan shroud (or that cover if you want to call it that) doesn't look good to me. Each fan should have a shroud that completely surrounds each fan to the exit point. To me it looks like they can blow air back into each other or themselves. See the open area of each fan? Not right to me. JMO

 

[SoCalDave]

Here you can see what I'm talking about. You can see from fan to fan, it shouldn't be that way as I'll bet your circulating hot or wasted air and not pulling enough through the radiator. Again JMO.

 

[LargeOrangeFont]

yes, and exactly why scoops may or may not do anything (or even make it worse). the problem may be at the fan shroud itslef and need additional ducting there or diverters to improve airflow in the back.

Agree.

 

[LargeOrangeFont]

Here you can see what I'm talking about. You can see from fan to fan, it shouldn't be that way as I'll bet your circulating hot or wasted air and not pulling enough through the radiator. Again JMO.

View attachment 1280997

That may be a cover, not part of the shroud (I haven’t seen under it) but is a restriction. I agree that the trouble shooting starts here, and on the intake side.

 

[LargeOrangeFont]

Easy if you don't have the optional rear skid plate. Otherwise you aren't securing a hitch/hook in the receiver until you cut the plate.

The one I’ve seen does not cover that area.

 

[HCP3]

The one I’ve seen does not cover that area.

Check out RD's video.

 

[hallett21]

This is a great thread if it can stay like this and not start all the shit talking. I have done my fair share of shit talking but now that the cars are out I really want to see the real world performance of it good or bad. Dave is off to a great start actually talking about the good and bad things of the car so far.

The over heating is a little concerning seeing as its only 86 degrees. My twin turbo sand car is heavy with full body and windshield and doesn't go over 190 in the dunes no matter what I'm doing. Dave has made some good adjustments so far to try and correct the problem. A few things to try. Is there any panels in the front of the car that are removable? And i'm saying like even down by your feet in the front? I know how any full body cars can vortex so anything letting more forward air come through will help. Next thing I would do is very aggressive but probably the best option. Raise the radiator up 6-8" to give it as much direct air as possible. We have done this on every sand car in our fleet because builders always seem to put them in very low. Raising them up helps tremendously. This is about the dumbest thing I will say but always have to ask, The fans are blowing the right direction correct? dumbest thing ever but we have had cars in our group that were blowing the wrong way and over heating.

Please keep the updates coming!

I was gonna ask if the fans were spinning correctly or not

 

[Outdrive1]

My last F150 had a fan fail. I bought an Autozone fan, threw it on, and two weeks later it was overheating again. Ended up going to the dealer and having them install a factory fan, everything was good after that. The point I’m making is that cheap Chinese fans seem to have shitty quality control.

 

[joecfd1]

I'm sure someone like Clint Berry/CBR Performance or Ron Davis will build a real radiator/fan shroud assembly to remedy this. Not going to be cheap but will most likely fix the problem.

 

[Bigbore500r]

Looking at the fan shroud (or that cover if you want to call it that) doesn't look good to me. Each fan should have a shroud that completely surrounds each fan to the exit point. To me it looks like they can blow air back into each other or themselves. See the open area of each fan? Not right to me. JMO

View attachment 1280994

It's hard to tell without seeing the bottom of the radiator, but if those fans are covering 80%+ of the surface area of the radiator, they are basically acting as their own shroud and the plastic piece is basically a decorative cover.......which might explain the large gaps, if it wasn't intended to be a shroud to begin with.

Shrouds are used to ensure the majority of the surface area of the radiator is having air drawn over it. If the fan layout / placement covers most of the radiator, the fans typically have a solid "ring" around the blades and that would act as a shroud to pull air across the fins.

 

[JayBreww]

Just curious, if it was to overheat and blow the motor with a windshield installed, is it covered under warranty?

 

[LargeOrangeFont]

Just curious, if it was to overheat and blow the motor with a windshield installed, is it covered under warranty?

FAFO.

 

[HCP3]

You mean this hitch from his video? You just have to run a shorter pin.

View attachment 1281055

It seemed like it was such a thick plate that no pin will get in there. Not the end of the world. Just a small oversight. Dave's eagle eye caught it.

 

[Flying_Lavey]

so one thing I haven't seen anybody mention and likely isn't the SOLE issue but is contributing......

The placement of that roof opening really looks like its in a horrible place. Almost looks like that would be in a negative pressure zone. Before doing anything else with that opening, Id try throwing tape across it and see if it feels any better. Or, maybe better yet, have a passenger ride along with some plastic and more it to different locations in the car to get an idea of wind patterns. Do it in the front and back seats. Once you have a good idea of where the air is in fact going, then you can make much more effective decisions.

 

[LargeOrangeFont]

so one thing I haven't seen anybody mention and likely isn't the SOLE issue but is contributing......

The placement of that roof opening really looks like its in a horrible place. Almost looks like that would be in a negative pressure zone. Before doing anything else with that opening, Id try throwing tape across it and see if it feels any better. Or, maybe better yet, have a passenger ride along with some plastic and more it to different locations in the car to get an idea of wind patterns. Do it in the front and back seats. Once you have a good idea of where the air is in fact going, then you can make much more effective decisions.

The roof scoops only job is to get a little air into the cabin area behind the windshield so there is not much negative pressure behind it.

I don’t think making it any bigger without directing the air into the rad inlet will help.

 

[Flying_Lavey]

The roof scoops only job is to get a little air into the cabin area behind the windshield so there is not much negative pressure behind it.

I don’t think making it any bigger without directing the air into the rad inlet will help.

I understand. But if it were positioned correctly it COULD negate the negative pressure zone behind the windshield. However it is too far back to do so. It looks like it would be right in the eddy coming off the top of the windshield at speed. Adding the lightbar in front of it as also disrupts the airflow over the top of the windshield furthering the ussues from no roof vent.

 

[PlanB]

Bigger fan on the radiator ? Possible shroud too ?

Shroud is what I was thinking. Our cobra has a sealed fiberglass shroud with two electric fans pulling air through. You can stand in front of the car and actually feel the air being pulled into the radiator. Cars without shrouds or without complete shrouds don't pull the same volume of air. I actually have a hard time getting the car to temperature at times because the cooling system is too effective.

 

[white tortilla]

How about wiring the fans backwards. Problem solved.

 

[37 boat]

i agree with this.......need a baseline of what temps the car sees without the windshield to see how bad the problem actually is. also need to make note of ambient temps as the car might be fine with the windshield as is in cooler weather. i would also vacuum the cooling system before doing anything to make sure there is no air in the system

I believe during one of the presentations Robby mentioned an air bleed in the cylinder head ( I'm not very familiar with LS engines but I think he compared it to them). I would think that would be self burping? Anyways as an early number customer I appreciate this thread and hope it stays on topic.

 

[rivermobster]

How about wiring the fans backwards. Problem solved.

I would definitely try reversing the fans before I got all crazy and shit.

 

[PlanB]

This shroud is completely sealed around the radiator. Pulls a ton of air.